Art of making metal castings.



No. 741,618- PATENTED OCT. 20,1903.

w. A mm ART OI MAKING METAL GASTINGS. Arrmonmn FILED APR. 1a. 1902.

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UNITED STATES i atentd October 20, 1905 PATENT OFFICE.

WILLIAM A. BOLE, OF PITTSBURG, PENNSYLVANIA, ASSIGNOR TO THEWESTINGHOUSE -MAOHINE COMPANY, A CORPORATION OF PENN- SYLVANIA.

SPECIFICATION forming part of Letters Patent No. 741,618, dated October20, 1903.

Application filed April 18, 1902.

My invention relates to the art of casting metal; and it has for itsobject to provide a method which shall insure substantially synchronouscooling, and consequently synchronous shrinkage of all portions of themetal constituting a casting or such other regulated cooling andshrinkage as shall tend to so con-. trol internal strains as to obviatedanger of rupture of the casting by reason of such strains. I Myinvention is illustrated in the accom" panying drawings, in which- 7Figure 1 is a vertical section through a sand mold provided with meansfor practicing my method, and Figs. 2 and 3 are respectively plan viewsof two of the coils shown in Fig. 1 through which cooling liquid iscirculated. In making castings which comprise unequal thicknesses ofmetal, particularly if the castings are of large size, some portionswill cool more rapidly than others, and it follows that the thicker andheavier sections continue to contract after the thinner sections have assumed their final dimensions, strains being thus produced in thecastings which are sometimes so serious as to cause the castings torupture, even While in the mold, and sometimes giving no visible sign oftheir existence until the skin of the castings is removed bymachining,when the internal stresses produce a rupture of the casting.Cases have been known in which the rupture due to internal strains tookplace months after the castings were made and without any previousvisible indication of the existence of such strains.

In the case of castings having different portions of unequal thicknessthe thicker portions obviously cool and solidify much more slowly thanthe thinner portions, this being specially pronounced where the outerportions are the thinner ones, since the more Serial No. 103,619. (Nomodel.)

rapid cooling incident to the lesserthickness of the metal is furtherenhanced by the more ready radiation of heat toward the outer surface ofthe flask or of the mold. By reason of this, unequal cooling lack ofuniformity of crystalline structure and consequently unspecially treatedwould not cool synchronously. In order to properly cool the thickerportions of the metal, I. provide the lower part or drag 4 of the moldwith a spiral coil 5, placed as close to the face of the mold as ispracticable, to which a cooling liquid,.such as water, is suppliedfrom asuitable source through a pipe 6, in which is a cock 7 for regulatingthe flow. The other end of the coil 5 communicates witha vessel 8 forreceiving the waste water through a pipe 9, thevessel 8 being connectedby a pipe 10 with a sewer or other suitable place for discharging thewaste water. The upper part or cope 11 of the mold is also providedadjacent to the face ofthe mold with a spiral coil 12, supplied withwater from a suitable source through a pipe 13, in which is a valve 14for regulating the flow. The other end of the coil also dischargesthrough a pipe 15 into the vessel 8. In this particular form of castingthe core 16, which provides the piston-rod opening,is also provided witha coil of pipe 17 ,here shown as having the form of a helix and asconnected at one end to a supply-pipe 18, having a regulating-valve l9,and as having its other end connected to a pipe 20, which dischargesinto the vessel 8.

In practicing my'method I first pour the molten metal into the mold, andafter the ladle is removed I open the cooks 7, 14, and 19 and thereafterregulate the flow of water SS balanced strains are present in-thecasting. r

different thicknesses of metal, which unless through the several coilsin accordance with the cooling effects desired by proper manipulation ofthe cocks.

The form, number, and location of the cooling-pipes will obviouslydepend upon the size and shape of the casting, and the apparatus shownis therefore to be understood as merely indicative of separate coolingmeans for different portions of the casting, the supply of coolingliquid being independently regulated in accordance with the form andsize of the casting, so as to insure practically synchronous cooling andhence synchronous and equalized contractions of the metal. It may besometimes desirable, however-as, for example, in the case of the pistonshown or in the case of a pulley-to cool the inner portions more rapidlythan the rim in order that the final shrinkage of the rim may serve tobind the structure together in a manner similar to that of a tire whichis shrunk upon the felly of a Wagon-wheel.

My method enables me to secure either a practically synchronousshrinkage or any artificial deviation therefrom which may be necessaryor desirable.

By employing the separate controlling devices 7, 14, and 19 for theseveral supplypipes and also providing means whereby the coils maydischarge separately it is possible to regulate the quantity of water ineach coil as may be necessary in order to produce the desired coolingeffect and to determine by feeling the temperature of the water as itdischarges from the pipes 9, 15, and 20 or by use of thermometers justwhat regulation of the supply is necessary in order to keep the coolingof all the parts of the casting uniform, or substantially so.

vI claim as my invention- 1. The improvement in the art of making metalcastings in sand molds, which consists in promoting approximatelysynchronous shrinkage of all portions of the metal by subjecting thesand which constitutes the mold, adjacent to difierent portions of thecasting, to the cooling action of independently-regulated quantities ofcooling fluid.

2. The improvement in the art of making metal castings in sand molds,which consists in promoting approximately synchronous shrinkage of allportions of the metal by sub jecting one or more portions of the sandconstituting the mold, adjacent to the casting, to the action ofindependently-regulated quantities of cooling fluid during the coolingoperation.

3. The improvement in the art of making metal castings, which consistsin promoting approximately synchronous shrinkage of all portions of themetal by subjecting any one or more of a plurality of different portionsof the sand which constitutes the mold, adjacent to the metal, to theaction of independentlyregulated quantities of cooling fluid during thecooling operation.

In testimony whereof I have hereunto subscribed my name this llth dayofApril, 1902.

WILLIAM A. BOLE.

Witnesses:

A. B. GRANGE, D. O. ARLINGTON.

